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What size big line kit do I need?


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Moparman says I need a big line kit with my raptor 100 on my 2001 stock Dodge. How big? Big lines all the way to the injection pump? I know about the high flow banjo bolts but are there big line banjo fittings? I am thinking about the XDP sump instead of a larger draw straw. Any thoughts on that? Can I still use the stock fuel filter?

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Do you already have the raptor? It will come with 3/8 or 1/2 line that runs from the tank to the raptor, then to the filter housing. Big line kit just replaces the banjo bolts on the filter housing and the injector pump and the small line inbetween the two. Unless you already have the intank pump, you will not need a draw straw, sump or any tank mods. Here is the one I have. http://www.vulcanperformance.com/Universal-Big-Line-Filter-to-Injection-Pump-Kit-w-p/ffip59.htm

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I love big line kit questions. I have yet to figure out how a 5.9 litre engine needs a 1/2 inch fuel line when for comparison our Cat 789 trucks with a 61 litre 4210 cubic inches 3516 engines with 2,000 horsepower with 4 turbos that runs at 2100 rpms runs off of a single #8 or 1/2 fuel line.I have asked this over many many forums over the years and have yet to get any good answers.:doh:Oh yeah ...........It sells lots of parts,Be realistic, the only restrictions are the banjo fitting at the pump and fuel filter housing, upgrade these and go with 3/8 and be done.

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I think a lot of the line requirements are based on the pump and the fittings. The pumps are rated at 0 psi, so they need all the help they can get. The quantity of fuel is plenty, but they seem to loose pressure faster than they should. Pressure is important for a VP, not so much for a CP3. I also think the suction line is undersized in many applications.

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Yeah I'm with W&F on this one. If you use the 103 MM3 thing for a 235@2700RPM 24V, that's 13.2 GPH or 0.22 GPM.

According to this http://www.dieseltruckresource.com/dev/showpost.php?p=965679&postcount=19 a 150GPH pump is making 126 at 20psi which is what everyone seems to be running pressurewise. Alright so welllll within it's capabilities.

Alright but that's a stock truck.. Using the 24V efficiency and putting in 400HP at 3000RPM I end up with a grand total of 22GPH.

In fact, if I reverse it all and use 126GPH at that efficiency and 3000RPM, that comes out to 2239HP.

So the pump isn't the problem.

So we are left with the pressure drop within the lines. Well here is calculated for 2 meters of 7mm line (I think thats the stock internal diameter). I used 22GPH being 400HP... Found out the the other specs through google.

Thats 0.19psi drop. In other words, the fittings are killing everything, not the lines.

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You calculated fuel being burned, but there is a LOT of fuel being returned. That return fuel is needed for cooling and lubricating parts. Doesn't a VP44 need 14 psi for proper lubrication? So a bigger pump is needed to keep up with 14 psi and the flow. A 480hp QSB 5.9 burns just under 26 gal/hr at rated rpm, but it also returns that much. Something else to consider is that some of the FASS's and some of the AD's (not Raptor/HPFP/DDRP) have a return line from the pump. So they are moving a lot of fuel thru the suction line, and the suction line can be the restriction. Generally the fuel lines are oversized, but the oversized lines also allow for a smaller pressure drop with a rapid power change, like you see on a pickup (racing, passing, etc). Where a bigger motor generally doesn't have the rapid fuel flow changes based on the application.

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I don't think that's it but you can go into more detail on it to prove me wrong. I think it's a problem with overflow valves. They don't have the precision they need in order to control flow. My truck stays above 30psi at WOT with tiny lines with the mechanical lift pump which TorkTek swears is completely worthless. My belief is that these fuel pumps can provide much more flow than the injection pump and the issue arises with the overflow valve being "tuned" to give you a max pressure. When I am on a downhill and leave it in gear and let off so that the engine can overspeed, giving the lift pump full RPM and the overflow full flow, my truck will see 40psi. Same scenario but WOT, I see more like 32psi. The overflow opens at 20psi though..if that. So at WOT the injection pump is fighting the overflow for fuel, and the pressure is still 32psi, meaning the lift pump is still providing plenty of fuel. If it got sucked down to 5psi then it would be obvious the lift pump was worn out or the overflow spring was very weak. Therefore, I believe a variable overflow valve is the solution. One with electronic controls and all that fanciness to open a needle valve or something to allow a steady pressure with little variation. I think a baffle or whatever its called also needs to be installed to get rid of the pulsations. The lines have plenty of flow for 400HP at 20psi so that gives you an idea of how much HP I can get running over 30psi. Another interesting thing. 12 valves seem to have 2 designs for their overflow valve. One has a hole that is maybe 3/16", the other is 0.08", which is what I have. I have read a lot about 12V's having poor fuel pressure and I am wondering if they all have the bigger diameter as mine sure has no fuel pressure issue whatsoever. So even if my spring was weak, the orifice is so small that is regulates pressure on it's own.

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30 psi with teeny lines is not the same flow as 30 psi with huge lines, as far as potential flow. If the pump places more restriction than the lines then its the same flow. The OEM LP on my truck starts to internally bypass at around 10 psi. By the time it gets to my pressure sender it's down to about 8 psi max. I can see the internal bypass spring working by the bouncing of the pressure ± 0.5 psi under light load. As my demand goes up, passing/towing, the pressure steadies as the bypass is below the cracking pressure. If I ease into full power, such as going from the flats to a 6% grade while towing, the pressure drop isn't huge; however, if I just slam it from cruise to WOT I can get a 2-3 psi drop over my towing WOT pressure. That tells me that the rate of demand for fuel has a large effect on pressure, but maybe not flow. 50 GPH thru a 1/2 hose will be lower pressure than thru a 3/8" hose, so I still don't see how people see increased pressure with a big line kit, unless the OEM lines are blocking flow. If the pressure goes up with the same pump and larger lines I would say the original lines were the restriction.

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30 psi with teeny lines is not the same flow as 30 psi with huge lines, as far as potential flow. If the pump places more restriction than the lines then its the same flow.

Are you sure? Because I'm going to toss this out there. At a factory we have a 4" main line for air pressure, then it feeds off through 1" lines and then it connects to the flexible air hose we all know and use, which one size would be 3/8". Another size is 3/4". I know a guy who has a 3/4" (I think) impact for putting on semi truck lugnuts. So we have 2 different air hoses. But the air in the hoses and the air in the 1" and 4" lines, all measure 120psi. Alright so lets say I have a 3/8" impact. On the 3/8" air line it runs fine. 3/8" Impacts are satisfied with 3/8" lines and do their job perfect. Why? Because the 3/8" air line is sufficient for it. Alright, now lets say I put a 3/4" adapter on it and hook it up to the 3/4" air line. What's the difference? Nothing. The impact is getting the max flow it can handle in either case. Meaning, "30psi with teeny lines is the same as 30psi with big lines" IF the thing it is supplying is the determining factor of flow. Meaning, the injection pump cannot flow more than the small lines can handle, so in either case of small or big lines, pressure is maintained and the volume of fuel delivered is still the same. In the case of the 3/4" impact, now I see where your law applies. It is practically like taking the end off the 3/8" line and letting it blow off. Velocity increases pressure drops. But I don't see it being the case with our trucks because the injection pump even with the overflow valve flow, is still the same as the 3/8" impact example because the lines flow more than the injection pump and the lift pump flows more as well, so my overflow thing is still my idea of the issue.
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I have 1/2 inch big line kits on both of our trucks. I realize they are probably a bit of overkill on my truck and massive overkill on her truck but for the reasons that AH64ID mentions about VP-44 cooling and to a minor degree, these bigger lines behave like a massive flexible fuel manifold that can help a small amount with fuel delivery under extreme load. The price difference is not that much between the 3/8" and 1/2" line. I would go with 1/2" everytime. It will work just fine with a stock engine and leaves you the option to go as big on hp as you want within reason. Just my :2cents:

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Are you sure? Because I'm going to toss this out there. At a factory we have a 4" main line for air pressure, then it feeds off through 1" lines and then it connects to the flexible air hose we all know and use, which one size would be 3/8". Another size is 3/4". I know a guy who has a 3/4" (I think) impact for putting on semi truck lugnuts. So we have 2 different air hoses. But the air in the hoses and the air in the 1" and 4" lines, all measure 120psi. Alright so lets say I have a 3/8" impact. On the 3/8" air line it runs fine. 3/8" Impacts are satisfied with 3/8" lines and do their job perfect. Why? Because the 3/8" air line is sufficient for it. Alright, now lets say I put a 3/4" adapter on it and hook it up to the 3/4" air line. What's the difference? Nothing. The impact is getting the max flow it can handle in either case. Meaning, "30psi with teeny lines is the same as 30psi with big lines" IF the thing it is supplying is the determining factor of flow. Meaning, the injection pump cannot flow more than the small lines can handle, so in either case of small or big lines, pressure is maintained and the volume of fuel delivered is still the same. In the case of the 3/4" impact, now I see where your law applies. It is practically like taking the end off the 3/8" line and letting it blow off. Velocity increases pressure drops. But I don't see it being the case with our trucks because the injection pump even with the overflow valve flow, is still the same as the 3/8" impact example because the lines flow more than the injection pump and the lift pump flows more as well, so my overflow thing is still my idea of the issue.

There are 3 parts to the equation. Pressure, flow, and resistance. Change one and the others will change too. I have seen a 3/4" impact wrench struggle with 3/8" line at 90 psi (psi set for the wrench) and a 200 gallon tank behind it, why? The 3/8" line doesn't flow what the wrench needed, even thou the pressure was there. If you have a open ended 3/8" line and an open ended 3/4" air line both hooked to a unlimited supply of 120 psi air, the 3/4" line will flow more air. That's the same thing with fuel lines and fuel, but if the customer of the air/fuel doesn't need what the supply line is capable of then the flow is the same.
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That's uh, exactly what I said.. And "but if the customer of the air/fuel doesn't need what the supply line is capable of then the flow is the same." was my point. The pump isn't even using what a 7mm line can flow, it only had a 0.9psi drop for 44GPH at 20psi. Yet people with big line kits are still seeing 2-3psi drop. I believe this to fully be the overflows fault because it is a stupid spring, it needs to be smarter and have a controller in order to compensate to an exact amount.

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There are 3 parts to the equation. Pressure, flow, and resistance. Change one and the others will change too. I have seen a 3/4" impact wrench struggle with 3/8" line at 90 psi (psi set for the wrench) and a 200 gallon tank behind it, why? The 3/8" line doesn't flow what the wrench needed, even thou the pressure was there. If you have a open ended 3/8" line and an open ended 3/4" air line both hooked to a unlimited supply of 120 psi air, the 3/4" line will flow more air. That's the same thing with fuel lines and fuel, but if the customer of the air/fuel doesn't need what the supply line is capable of then the flow is the same.

It comes down to the fittings the same as the restrictive banjo fitting on our rigs. The factory line will " except for the wee thing between the fuel canister and Vp44" supply the needs of 90% of the rigs out there unless making super Hp #'s. I laugh when I go into people shops and they have the 3/4 inch air lines and then use the same 1/4 inch quick connect fittings on the gun as they use on every other air tool in the shop, this is where the problem lies. I have seen numeraous 3/4 inch air guns with 3/8 pipe throats on them from factory too, all the 3/4 inch air line in the world will not overcome the restrictive fittings. Our rigs have enough flow to handle all the needs an a whole lot more with 3/8 line if one just gets the better flowing banjo bolts. Back to your comment several threads back about hot rods and equipment running at rated speed ect, My example of our big 2000hp trucks are no different that a pickup as far as driving goes, regular foot pedal and they go from wide open to idle all day long they accelerate just like a car 6 speed automatic and all. And still only a 1/2 inch fuel line feeding the monsters.
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And still only a 1/2 inch fuel line feeding the monsters.

With what size of a fuel pump? I agree on the fittings, I run better pressure than a lot of folks with stock pumps and my power level, but have upgraded all the banjo's to high flow banjo's or JIC AN fittings. So even with 3 filters I have no fuel pressure issues at 415/850+.

That's uh, exactly what I said..

I'm still on my first cup of coffee this morning. I wrote most of that after reading the first 2 paragraphs of yours :-)
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With what size of a fuel pump? I agree on the fittings, I run better pressure than a lot of folks with stock pumps and my power level, but have upgraded all the banjo's to high flow banjo's or JIC AN fittings. So even with 3 filters I have no fuel pressure issues at 415/850+. I'm still on my first cup of coffee this morning. I wrote most of that after reading the first 2 paragraphs of yours :-)

I am not sure of the flow rate of the pump but it is a small " fit in the palm of your hand" fixed displacement engine mounted mechanical driven gear pump and they run a regulated "Orificed fitting post pump" system pressure of around 18-28 psi depending on the application.
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